1. Field of the Invention
The present invention relates to a halogenation process for polymers with improved neutralization of the hydrogen halide by-product resulting from the halogenation.
2. Description of Information Disclosures
Halogenation processes in which a polymer is reacted with a halogenation agent to produce a halogenated polymer containing chemically bound halogen and a hydrogen halide by-product followed by neutralization of the hydrogen halide by-product by contacting the halogenation reaction product with an alkaline material which reacts with the hydrogen halide by-product are well known.
It would be desirable to increase the rate of neutralization to minimize the possibility of incomplete neutralization, discoloration of the halogenated polymer and, thereby, increase the stability and consistency of the halogenated polymer.
The neutralization reaction rate for neutralizing a halogenation reaction product comprising certain halogenated polymers, which will be subsequently described, is particularly slow and in need of improvement.
U.S. Pat. No. 2,732,354 discloses chlorination of an interpolymer of an isoolefin and a polyolefin dissolved in a solvent. The halogenation reaction product is neutralized in an equivalent amount of potassium hydroxide in methanol (see col. 6, lines 44 to 47).
British patent 746,692 discloses reacting iodine monochloride in carbon tetrachloride with an interpolymer of isobutylene and isoprene dissolved in heptane to produce the corresponding iodine and chlorine--containing interpolymer, and neutralizing the product with an equivalent amount of potassium hydroxide dissolved in methanol (see col. 5, lines 92 to 95).
It has now been found that the presence of a critical limited amount of an alcohol during the aqueous neutralization reaction of the halogenation product will increase the neutralization rate.